With the rapid development of semiconductor technologies, the feature size of semiconductor devices continues to decrease. A reduced feature size means that a larger number of transistors can be arranged on a chip, which meets higher requirements for the semiconductor manufacturing technologies.
Semiconductors (e.g., a gate and source/drain doped regions) and external circuits are usually electrically connected with each other via a metal plug. However, since the Fermi energy levels of a metal and a semiconductor are quite different, the potential barrier between the metal plug and the semiconductor is relatively high, resulting in a very large contact resistance between the metal plug and the semiconductor. Conventionally, the contact resistance is reduced by forming a metal silicide between the metal plug and the semiconductor, thereby improving the performance of semiconductor structures.
However, semiconductor structures formed by conventional technologies still have a large contact resistance between the metal plug and the semiconductor. The disclosed semiconductor structure and method are directed to solve one or more problems set forth above and other problems in the art.